1. Field of the Invention
The present invention relates to an ink jet head for generating fine recording droplets used for the ink jet recording method, and also, relates to the method of manufacture therefor. More particularly, the invention relates to a water-repellent process applied to the surface of the head.
2. Related Background Art
For the ink jet head applicable to the ink jet recording method, there have been made various proposals to enhance the performance thereof, such as to obtain a higher image quality at higher speed, among some others. The applicant hereof has made such proposals in Japanese Patent Application Laid-Open No. 04-10940 to Japanese Patent Application Laid Open No. 04-10942, which present ink jet recording methods that make higher image quality possible.
Also, the applicant hereof has proposed in the specification of Japanese Patent Application Laid-Open No. 06-286149 a method for manufacturing an ink jet recording head, which is more preferable than the ink jet recording methods disclosed in the specifications of the aforesaid Japanese Patent Application Laid-Open Nos. 04-10940 to 04-10942. Further, the applicant hereof has proposed separately the water-repellent composition optimally usable for the ink jet head and the mode of utilization thereof a method for burying a water-repellent member on the recessed portion formed on the surface of a head, and the like with respect to the water-repellent process of the head surface.
Also, regarding the water-repellent process of the head surface, the applicant hereof has proposed in Japanese Patent Application Laid-Open No. 06-210859 a method for improving print quality with the provision of a water-repellent area and a non-water-repellent area for the nozzle surface. In other words, in the specification thereof, it is disclosed that when the entire area of the nozzle surface is made water-repellent, ink mist is integrated to become the ink droplet at the time of continuous printing or the like, which is sucked into the discharge port, and may cause non-discharge to occur. On the other hand, according to such disclosure, if the nozzle surface is partially provided with a hydrophilic portion, it becomes possible to collect ink mist on the hydrophilic portion and prevent it from being incorporated into droplets.
However, in accordance with the method disclosed in the specifications of aforesaid Japanese Patent Application Laid-Open Nos. 04-10940 to 04-10942, and the optimal method of manufacture disclosed in the specification of the aforesaid Japanese Patent Application Laid-Open No. 06-286149, the nozzle formation member and the water-repellent member are formed altogether by means-of patterning exposure and development process. This formation brings about a mode in which the water-repellent member remains on the nozzle surface under any circumstances. Therefore, it, is difficult to improve the print quality with the provision of a water-repellent area and a non-water-repellent area as disclosed in the aforesaid Japanese Patent Application Laid-Open No. 06-210859.
Meanwhile, for the improvement of print quality with the provision of the water-repellent area and the non-water-repellent area for the nozzle surface as disclosed in the specification of Japanese Patent Application Laid-Open No. 06-210859, it is arranged to remove the water-repellent material locally by ablation given by the application of excimer laser after the water-repellent member is formed uniformly on the nozzle surface. As a result, there may occur residues by the ablation, and also, it is difficult to make positioning with the discharge ports precisely, thus leading inevitably to the increased numbers of processing steps among some other disadvantages. Here, therefore, the method still has room for improvement.
Here, the present invention is designed with a view to solving the aforesaid problems. It is an object of the invention to provide an ink jet head capable of providing the water-repellent area and non-water-repellent area for the nozzle surface with the formation of the water-repellent portion and hydrophilic portion for the nozzle surface thereof in exact positioning precision without increasing the number of processing steps, thus enhancing print quality, and also, to provide the method of manufacture thereof.
In order to solve the problems described above, the present invention provides a method for manufacturing an ink jet head, the structure of which is arranged as given below.
The method for manufacturing the ink jet head, which is provided with a discharge port member having discharge ports for discharging ink arranged therefor, comprises the steps of forming an ink flow-path pattern from a soluble resin on a substrate having an ink discharge pressure generating element formed thereon; laminating on the ink flow-path pattern a first photosensitive resin layer for forming the discharge port member; laminating on the first photosensitive resin layer, a second photosensitive resin layer having water-repellency for forming the discharge port member; forming a first latent-image pattern reaching the bottom portion of the first photosensitive resin layer, and a second latent-image pattern extending beyond the second photosensitive resin layer but not reaching the bottom portion of the first photosensitive resin layer, by subjecting the first photosensitive resin layer and second photosensitive resin layer to a pattern exposure simultaneously by use of mask, while controlling partially the exposed area of the exposed portion at the time of applying the pattern-exposure so as to make the depths of latent images produced by the pattern exposure different; forming a hydrophilic portion having the discharge port and first photosensitive resin layer exposed by developing the pattern-exposed first photosensitive resin layer and second photosensitive resin layer; and removing the ink flow-path pattern formed from the soluble resin.